Tuning the Sun's Rays Feature Summary

The photo (hi-res version) shows an intense beam of filtered sunlight (green) which is "up-converted" to blue light (this process is called up-conversion because blue light has a higher frequency than green light). To learn how it's done, see Tuning the Sun's Rays from the American Physical Society's Physical Review Focus. You can find out how frequency is related to photon energy at Physics 2000's Plank's Constant and the Energy of a Photon, and for more, visit the rest of the Quantum Atom section on the same site.